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Caramelised onion tart, onion tart, onion quiche, caramelised onion quiche

Caramelised Onion Tart

  • Author: Tastebotanical
  • Prep Time: 15
  • Cook Time: 55
  • Total Time: 1 hour 10 minutes
  • Yield: 1 tart serving 8 people 1x
  • Category: Tart
  • Method: Baking
  • Cuisine: English


This luscious tart is filled with caramelised onions, subtly flavoured with nutmeg, set in a rich cheese custard.  It is fantastic for hot, warm or cold which makes it very versatile.  I honestly believe this is the best onion tart!



For the pastry:

  • 275 g plain flour
  • 125 g fat (I use a mix of half butter and half Trex as I think this makes the lightest pastry)
  • Salt
  • A little water

For the filling:

  • 6 large onions (white or red is fine) plus a further 3-5 onions or shallots for decoration
  • 40 g butter and 1 tbs oil
  • Salt and pepper
  • 1 tsp brown sugar (optional)
  • Grated nutmeg  (best to grate this from a whole nutmeg as this has best flavour)
  • 100 ml double cream
  • 2 eggs
  • 100 g strong cheddar cheese (grated)
  • A little olive oil


  1. Set your oven to 180 C, 350 F or Gas Mark 4.
  2. Make the pastry. Put the flour in a bowl.  Add the fat and combine –  either by “rubbing in” by hand or processing – until the mixture resembles breadcrumbs.  Season with salt and pepper.  Add a little cold water (2-3 tbsp) and shape the mixture into a dough.
  3. Peel and chop the onions.
  4. Heat the butter and oil in your frying pan.   It helps if the pan is good quality with a thick bottom as this will disseminate the heat evenly and prevent burning.
  5. Add the onions to the pan, season with salt and pepper,  and cook at a very low heat for about 30 minutes.  Keep an eye on them to make sure they are not burning and stir occasionally.  The onions are done when they are light brown, soft and, when tasted, are sweet.
  6. Season the onions with the grated nutmeg to taste (about half a tsp – although I add a bit more as I like it!).   You can add a tsp of brown sugar to increase  the sweetness of the onions at this stage if you wish.
  7. Set the onion mixture aside to cool slightly.
  8. Roll out your pastry and use it to line your quiche or flan dish.   Bake for 5  minutes in the oven to allow the pastry to “set”.  This will stop the filling making it soggy!
  9. Crack the eggs into a mixing bowl, add the cream, and beat until combined.  Finely grate the cheddar cheese and add to the mixture.
  10. Now place the onion mixture in your pastry case.  Pour the egg mixture over it.
  11. Thinly slice the onions or shallots that you have set aside for decoration.  The aim is to have a number of different sized circles of onion or shallot which you can use to decorate the top of the tart.  Arrange artistically (!) and then brush with a little olive oil and season with salt and pepper.
  12. Place your quiche or flan dish in the oven and cook for 25 minutes.
  13. The tart can be eaten hot, room temperature or cold.

Keywords: onion, tart